In the disc brake field, manufacturing of the braking disc in two separate pieces is known and appreciated: the support bell and the braking band.
This technical solution involves considerable advantages. First of all, it allows the braking band, which may reach high temperatures during the braking, to expand without being affected by any constraint imposed by the support bell. Moreover, this solution allows the two pieces to be manufactured in materials which are different from one another and such as to optimize the braking disc overall performance.
The solution selected for the structural connection between the band and the bell also decisively contributes to obtain some advantages.
For example, it is known to obtain the whole braking disc during a single manufacturing process, though using different materials for the band and the bell. This result can be achieved for example by a co-casting process.
It is also known to provide the braking band and the support bell independently from each other in order to subsequently form the braking disc only upon assembling.
This solution involves the use of a so-called drive connection, i.e. of further means adapted to structurally connect the bell and the band, thus ensuring the braking torque transmission and the desired backlashes or gaps.
In some specific fields, for example within the field of the high-performance and competition motorcycles, the drive connections which ensure a considerably easy mounting, besides ensuring all the above advantages, are particularly appreciated.
These drive connections further allow the only braking band to be quickly replaced, for example if the latter is worn, with no need for the support bell to be also replaced.
It is known from US 2005/0145452 a braking disc in which the band and the bell are assembled by means of an axial movement allowing to couple the bell axial protrusions with the band inner radial protrusions. The assembling ends with the application of an elastic retainer which can be locked in position for example by means of riveting. This solution, though requiring a small number of pieces, does not allow an easy assembling of the braking disc and above all it does not allow the disassembling thereof after it has been assembled.
It is also known from PCT WO 2005/088152 a drive connection which uses a plurality of plates, each of which connects a band inner radial protrusion to a bell outer radial protrusion. Each of said plates is fastened by means of two screw-nut screw couplings. A large number of pieces to be assembled and, accordingly, a high complexity of the assembling and disassembling operations of the braking disc derive from this technical characteristic.